Biomedical subjects
Publications and source records attributed to T J Wang.
OBJECTIVE: To study the chemical constituents of processed green tangerine peel(Citrus reticulata). METHOD: Using chemical techniques and spectroscopic analysis. RESULT: Four compounds were isolated from the peel and identified as hesperidin, neohesperidin, nobiletin and tangeritin. CONCLUSION: The compounds were obtained from this peel for the first time.
BACKGROUND: Over the past decade, calcium channel blockers (CCBs) and ACE inhibitors have been used increasingly in the treatment of hypertension. In contrast, beta-blocker and diuretic use has decreased. It has been suggested that pharmaceutical marketing has influenced these prescribing patterns. No objective analysis of advertising for antihypertensive therapies exists, however. METHODS AND RESULTS: We reviewed the January, April, July, and October issues of the New England Journal of Medicine from 1985 to 1996 (210 issues). The intensity of drug promotion was measured as the proportion of advertising pages used to promote a given medication. Statistical analyses used the chi2 test for trend. Advertising for CCBs increased from 4.6% of advertising pages in 1985 to 26.9% in 1996, while advertising for beta-blockers (12.4% in 1985 to 0% in 1996) and diuretics (4.2% to 0%) decreased (all P<0.0001). A nonsignificant increase was observed in advertising for ACE inhibitors (3.5% to 4.3%, P=0.17). Although the total number of drug advertising pages per issue decreased from 60 pages in 1985 to 42 pages in 1996 (P<0.001), the number of pages devoted to calcium channel blocker advertisements nearly quadrupled. CONCLUSIONS: Increasing promotion of CCBs has mirrored trends in physician prescribing. An association between advertising and prescribing patterns could explain why CCBs have supplanted better-substantiated therapies for hypertension.
The prostate-specific antigen (PSA) immunoassay is an important tool for the detection and monitoring of prostate cancer. PSA exists in serum mainly as complexes with serine protease inhibitors including alpha1 antichymotrypsin (ACT) and alpha2 macroglobulin (MG). PSA-MG complex is not detected by the existing PSA immunoassays since MG (720 kDa) sequesters PSA and masks the antibody binding sites. Existing immunoassays for quantitation of total serum PSA measure PSA-ACT (CPSA) and free PSA (FPSA), which comprise the major and minor components of total PSA, respectively. Monoclonal antibodies (MAb) specific for CPSA alone were generated using a unique immunogen prepared by blocking the major antigenic determinants on FPSA and ACT. The blocked immunogen greatly enhanced the frequency of hybridomas reactive against the CPSA complex. CPSA prototype immunoassays were established using anti-CPSA (PX1G359) or anti-ACT (AC1A212) MAb as tracer MAb and anti-PSA (PSA399) MAb as capture MAb. The complex-selective MAbs demonstrated minimal cross-reactivity with Cathepsin-G (CG) ACT (CG-ACT), ACT or FPSA. CG-ACT complex interfered with the accuracy of initial prototype assays specific for CPSA measurement and caused over-recovery (1 to 3 ng/mL, with 40 to 180 ng/mL range of CG-ACT in serum) of apparent CPSA values. Addition of 0.4% NP-40 and 0.1% 0.088 micron microparticles in clinical specimens eliminated this interference. Specimens from 39 prostate cancer (PCa) patients and 44 benign prostatic hyperplasia (BPH) patients were analyzed with the PX1G359 CPSA assay. In this study, the area under the curve (AUC) values for ROC analysis of total PSA (CPSA+FPSA), FPSA to total PSA ratio (f/t), and FPSA to CPSA ratio (f/c) were 0.357, 0.634, and 0.624, respectively. In a second study using AC1A212 CPSA assay, where specimens from 16 PCa patients and 48 BPH patients were tested, the AUC values for total PSA, f/t and f/c ratios were 0.62, 0.785, and 0.732, respectively. Using the CPSA assay with minimal interference our studies are consistent with previous CPSA data showing that the f/t PSA ratio remains superior to the f/c PSA ratio in differentiating PCa and BPH diseases. Complex PSA by itself or as ratio with free or total PSA does not provide any advantage over the established method of FPSA to total PSA ratio.
PURPOSE: Recent investigations have indicated that factors within the seminal plasma may contribute to the condition of low sperm motility in men with spinal cord injury. To determine whether the prostate gland functions normally in these men we chose prostate specific antigen (PSA) as a marker of prostatic function, and compared serum and semen concentrations in spinal cord injured and healthy noninjured men. MATERIALS AND METHODS: The study included 21 spinal cord injured men (mean age 33.3+/-1.2 years) and 22 noninjured normal men (mean age 30.3+/-1.5 years). Blood was obtained from subjects following at least 24 hours of abstinence from ejaculation and serum PSA was determined by modified enzyme immunoassay. Antegrade ejaculates from all subjects were frozen to -80 C, exactly 15 minutes after collection. Seminal plasma PSA was determined using Hybritech Tandem MP assay. RESULTS: Mean serum PSA concentration was 1.20+/-0.19 ng./ml. in spinal cord injured and 0.69+/-0.07 ng./ml. in noninjured men (p<0.02). Mean seminal plasma PSA concentration was 0.59+/-0.11 mg./ml. in spinal cord injured and 1.29+/-0.15 mg./ml. in noninjured men (p<0.001). CONCLUSIONS: Our findings of elevated serum and decreased seminal plasma PSA concentrations indicate that prostatic secretory dysfunction is present in men with spinal cord injury.
Immunoassays for prostate-specific antigen (PSA) using monoclonal or polyclonal antibodies have clinical applications, such as monitoring and early detection of prostate cancer. However, PSA shares 80% sequence homology with human glandular kallikrein (hK2). In the present study, we have used SDS-PAGE and Western blotting of a recombinant form of hK2 to determine the degree of cross-reactivity in a panel of 83 antibodies submitted to the ISOBM TD-3 PSA Workshop. From this panel, 24 of the 83 antibodies showed cross-reactivity with hK2. The majority of these antibodies showed binding to conformationally independent or linear epitopes. Fourteen of these antibodies appear to map to the same epitope group, indicating the existence of a dominant and linear immunogenic domain shared by PSA and hK2.
Approximately 40% of the prostate-specific antigen (PSA) purified from seminal fluid comprises cleaved or fragmented forms of PSA. These fragments are observed by reduced SDS-PAGE and have been identified in preparations of purified seminal plasma. The comparative analysis of 53 antibodies, submitted to an international PSA Workshop, with different PSA variants was studied using SDS-PAGE and Western blotting. Six different patterns of reactivity were observed which may reflect different epitopes recognized by this panel of antibodies. Additional antibody studies to nonreduced intact PSA suggest the epitopes are conformation-dependent.
BACKGROUND: Alterations in mass loading have been shown to stimulate the pituitary-gonadal and pituitary-adrenal axes resulting in changes in testosterone (T) and corticosterone (B) production which may account for the previously reported variations in muscle mass under these conditions. HYPOTHESIS: Centrifugation and hindlimb suspension will induce opposing effects on testosterone and corticosterone excretion. METHODS: Effects of mass loading (centrifugation at -2Gx) and unloading (hindlimb suspension, HLS) on excreted T and B levels, and testicular mass were examined in Sprague-Dawley rats. For 12 d, 16 (8 controls and 8 centrifuged) rats and 20 (10 unsuspended controls and 10 suspended) rats were studied during the centrifugation and suspension portions of the study, respectively. Following the completion of each study, testicular mass was measured. RESULTS: Absolute testicular mass was not different, following 12 d of centrifugation. Excreted T was elevated between days 1 and 6 of centrifugation. Excreted B levels were elevated for the first 4 d of centrifugation. Suspension reduced absolute and relative testicular mass. Excreted T levels were reduced from days 3-12 of suspension, while excreted B levels were only elevated on the first day of suspension. CONCLUSIONS: Centrifugation stimulated an increase in T excretion despite a lack of a change in absolute testicular mass. Conversely, suspension resulted in a reduction in T excretion which may have been associated with a decrease in absolute testicular mass. The centrifugation-induced increase in T excretion is consistent with previously reported increases in lean body mass following centrifugation, while the HLS-induced reduction in T excretion correlates with previously reported decreases in lean body mass following suspension.
A cystic hygroma was found in a full-term (39 week-old) male newborn delivered by cesarian section. Polyhydramnios was diagnosed by sonography at 21 weeks of gestation. Clinical manifestations at birth, such as respiratory distress, tachypnea and chylothorax were successfully relieved by the insertion of chest tube and medical therapy. Other conditions, which included mild hydronephrosis of left kidney, thickening of aortic and pulmonary valves with mild mitral and tricuspid valves regurgitation, subsided within six months. The cystic hygroma regressed to a webbed neck. In general, the features and clinical manifestations of the present case resembled the criteria of Noonan syndrome including various congenital heart defects; webbed neck; chest deformity; a characteristic facial appearance comprising of a broad forehead, ocular hypertelorism, antimongoloid slant of palpebral fissures, low set ears; and bilateral undescended testis etc., suggested by Noonan and other subsequent authors. The outcome of this infant was satisfactory following medical and surgical therapy (chest tube, orchiopexy) and a special dietary regimen.
BACKGROUND: A reduction in vasopressin was attributed to the initial diuresis reported in rats exposed to chronic centrifugation. However, it was suggested that urea may also contribute an osmotic component to this observed diuresis. HYPOTHESIS: Increased urea excretion will contribute to osmotic excretion during chronic centrifugation, which may be partly responsible for the initial diuresis previously observed. METHODS: Eight Sprague-Dawley rats were centrifuged (12 d at -2Gx) and eight were used as a control group. Daily urine samples were collected and an aliquot measured for excreted solutes and aldosterone. RESULTS: Urine volume was elevated over the first 7 d of centrifugation with a peak on day 4. Urea and osmotic excretion were elevated over the first 5 d. Excreted Na+ was elevated on days 1 and 2, which coincided with an increase in excreted aldosterone over the first 3 d of centrifugation. Urea excretion accounted for up to 54% of the increase in osmotic excretion during the initial portion of centrifugation suggesting that urea was, in part, responsible for the observed increase in urine output despite a reduction in water consumption. Following the first day of centrifugation, aldosterone appears to regulate Na+ as suggested by the reduction in Na+ excretion between days 2 and 3 when aldosterone excretion was elevated. CONCLUSIONS: It would appear that centrifugation induced an acute increase in protein catabolism as indicated by the increase in urea excretion which resulted in an increase in obligatory water loss. This increased diuresis may have acute consequences on the hydration state of centrifuged rats.
Castability of Ti-6Al-7Nb alloy, CP Ti, and Co-Cr alloy was examined for mesh type and plate type specimens. The casting was carried out with a pressure type casting machine and commercial molding material. The castability of the mesh type specimen was evaluated in terms of the number of cast segments (castability index), and that of the plate type was evaluated by the area of the specimen (casting rate). X-ray images processed by a digital imaging technique were used to identify the casting porosity. The casting rate of the specimens increased with increasing thickness of the specimens. It was concluded that the castability index and the casting rate of Ti-6Al-7Nb alloy was slightly lower than that of CP Ti, and higher than that of Co-Cr alloy, were as Ti-6Al-7Nb alloy showed fewer casting porosities than CP Ti and smaller ones than Co-Cr alloy, which was advantageous for increasing the reliability of the casting properties.
HL-60 cells were treated by isoverbascoside with different time and different concentrations in vitro. The differentiation of HL-60 cells was evaluated by light and electron microscopy to observe morphological changes, by chemiluminence to detect phagocytosis and by tumorigenesis in nude mice to determine malignancy. The cytotoxical effect of isoverbascoside on HL-60 cells was examined by trypan blue excluding staining and electron microscopy. The influence of isoverbascoside on cell cycle was measured by flow cytometry. Granular differentiation of HL-60 cells was induced by isoverbascoside at 20-25 mumol/L within 1-3 days as the results of morphological changes, enhancement of phagocytosis and decreasing of tumorigenesis. Strong cytotoxicity was evidenced in HL-60 cells treated by isoverbascoside at 30-35 mumol/L. HL-60 cells treated by isoverbascoside at 20 mumol/L were delayed at G1 phase at 12 hours and G2/M phase at 72 hours.
BACKGROUND: Prior studies suggest underuse of beta-blockers in patients with coronary artery disease, but these studies have been based on selected populations of recently hospitalized patients. OBJECTIVE: To describe national patterns and determinants of beta-blocker use in the ambulatory setting. METHODS: We analyzed 11745 visits by patients with coronary artery disease to randomly selected, office-based physicians in the National Ambulatory Medical Care Surveys for 1980, 1981, 1985, and 1989 through 1996. We used multiple logistic regression to determine the independent effect of sociodemographic and clinical factors on beta-blocker use. OUTCOME MEASURE: Beta-blocker use at patient visits. RESULTS: Beta-blocker use was reported in only 20.9% of office visits by patients with coronary artery disease and no strong contraindications between 1993 and 1996. In multivariate analyses, age younger than 75 years, residence in the Northeast, and visits to cardiologists and internists compared with family and general practitioners predicted greater use of beta-blocker therapy. White race and private insurance also were significant predictors of beta-blocker use between 1980 and 1996. Longitudinal analyses revealed a significant decline in beta-blocker use from 1980 to 1990, followed by a gradual increase in recent years. CONCLUSIONS: Beta-blockers appear to be underused in ambulatory patients with coronary artery disease. Our data suggest that nonclinical factors may influence rates of use, indicating the need for closer scrutiny of variations in physician prescribing practices.
BACKGROUND: Cardiac involvement is common in acute Lyme disease, and case reports suggest that cardiac abnormalities might also occur years after the primary infection. OBJECTIVE: To determine the prevalence of cardiac abnormalities in persons with previously treated Lyme disease. DESIGN: Population-based, retrospective cohort study with controls. SETTING: Nantucket Island, Massachusetts. PARTICIPANTS: From among 3703 adult respondents to a total-population (n = 6046) mail survey, 336 (176 case-patients and 160 controls) were randomly selected for clinical evaluation. MEASUREMENTS: Current cardiac symptoms and major or minor abnormal electrocardiographic features, including heart rate; rhythm; axis; PR, QRS, and QT intervals; QRS structure; atrioventricular blocks; and ST-segment and T-wave changes. RESULTS: Persons with Lyme disease (case-patients, n = 176) (mean duration from disease onset to study evaluation, 5.2 years) and persons without evidence of previous Lyme disease (controls, n = 160) did not differ significantly in their patterns of current cardiac symptoms and electrocardiographic findings, including heart rate (P > 0.2), PR interval (P = 0.15), QRS interval (P > 0.2), QT interval (P > 0.2), axis (P > 0.2), presence of arrhythmias (P > 0.2), first-degree heart block (P = 0.12), bundle-branch block (P > 0.2), and ST-segment abnormalities (P > 0.2). In multivariate analyses that adjusted for age, sex, and previous heart disease, a history of previously treated Lyme disease was not associated with either major (odds ratio, 0.78; P > 0.2) or minor (odds ratio, 1.09; P > 0.2) electrocardiographic abnormalities. CONCLUSION: Persons with a history of previously treated Lyme disease do not have a higher prevalence of cardiac abnormalities than persons without a history of Lyme disease.
With the aim of applying a novel titanium alloy, Ti-6Al-7Nb, to a dental casting material, a comprehensive research work was carried out on its characteristics, such as castability, mechanical properties and corrosion resistance in the present study. As a result, Ti-6Al-7Nb alloy exhibited sufficient castability by a dental casting method for titanium alloys and enough mechanical properties for dental application. It is also showed excellent corrosion resistance through an immersion test in 1.0% lactic acid and an anodic polarization test in 0.9% NaCl solution. From these results, it is concluded that this Ti-6Al-7Nb alloy is applicable as a dental material in place of Ti-6Al-4V alloy, which includes cytotoxic vanadium.
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OBJECTIVE: To study the outcome of Lyme disease (LD) in children identified in a total population survey of an endemic island. METHODS: We conducted a population-based retrospective cohort study off the coast of Massachusetts. Twenty-five children who met the Centers for Disease Control case definition for prior LD were compared with 26 children without LD from the same community. All children with LD received antibiotics during the acute phase of their disease. All 51 children were invited for a clinical evaluation, including 12-lead electrocardiogram (EKG), and measurement of antibodies to Borrelia burgdorferi by antibody-capture ELISA and Western blot. RESULTS: At a mean of 3.2 years from the initial manifestation of LD, children with prior LD did not have a higher prevalence of musculoskeletal or neurological symptoms, examination abnormalities, abnormal EKG, or behavioral difficulties, compared to children with no history of LD. CONCLUSION: Children who receive appropriate antimicrobial therapy for LD appear to have no demonstrable longterm morbidity.
The present study describes the ultrastructural synaptic relationships between corticocuneate terminals (CCTs) and glycine-immunoreactive (glycine-IR) neurons in the cuneate nucleus of rats using anterograde tract-tracing of wheatgerm agglutinin conjugated with horseradish peroxidase (WGA-HRP) and anti-glycine immunoperoxidase labeling methods. The HRP-labeled CCTs made axodendritic synapses preferentially in the ventral part of the cuneate nucleus near the obex. In a total of 182 CCTs surveyed, 14 of them made direct synaptic contacts with immunoperoxidase-labeled glycine-IR dendrites. The present results suggest that cortical modulation on the sensory transmission of cuneate nucleus may be mediated through glycine-IR neurons.
A meta-analysis of six case-control studies on the relationship between reported exposure to environmental tobacco smoke (ETS) and lung cancer in nonsmoking Chinese women was performed, using the fixed-effect model. A total of 767 cases and 1193 controls from Shanghai, Guangzhou, Shenyang, Harbin, Xuanwei, and Hong Kong were reported in five of these six studies. (One study did not provide a clear description of the number of cases and controls). The Fleiss method was used to calculate the overall odds ratio (OR), the test of average degree of association (chi 2 assoc), the degree of homogeneity (chi 2 homog) and the 95% confidence interval (CI). The overall OR of lung cancer risk in nonsmoking Chinese women from exposure to ETS is 0.91 (95% CI, 0.75-1.10, chi 2homog = 4.51, P > 0.25). No statistically significant relationship was found between either the amount (cigarettes/day) or the duration (in years) of exposure to ETS and lung cancer. Bias and confounding factors are briefly discussed.